Heat exchanger with cold reservoir

ABSTRACT

The invention relates to a heat exchanger, in particular, an evaporator ( 1 ), in particular for a motor vehicle air-conditioner, with a number of closely arranged refrigerant tubes and at least one cold reservoir ( 4 ), in which a refrigerant medium is provided. The evaporator ( 1 ) comprises two parallel regions ( 1 ′ and  1 ″) running across the total width, the first region ( 1 ′) corresponding to a conventional evaporator in design, the cold reservoir ( 4 ) being arranged in a separate second region ( 1 ″), through which at least a partial flow of refrigerant can flow which also flows through at least a part of the first region ( 1 ′) and the first and the second region are connected to each other by at least one overflow opening ( 13 ).

The invention relates to a heat exchanger, in particular for a motor vehicle air conditioning system, with cold store according to the preamble to claim 1.

It is an aim of the motor vehicle manufacturers to reduce the fuel consumption of the vehicle. One measure for reducing the fuel consumption is to cut off the engine when the vehicle is temporarily stationary, for example when stopping at traffic lights. This temporary cutoff of the engine is also referred to as idle-stop operation. In modern low-consumption vehicles, such as, for example, in the so-called three-liter vehicle, this measure is already being used. In vehicles boasting the idle-stop operating mode, the engine is cut off for about 25-30% of the journey time in inner-city traffic.

This is a reason why such vehicles are often not equipped with an air conditioning system, for when the engine is shut down, nor can a compressor necessary for an air conditioning system be driven, so that in idle-stop operation an air conditioning system cannot provide the necessary cold capacity. The problem is also partially solved by the fact that, when the air conditioning system is switched on, the engine continues running during a stop, whereby, however, a higher fuel consumption is obtained.

In DE 101 56 944 A1 there is disclosed an air conditioning system for a motor vehicle, having a compressor and an evaporator, disposed in a refrigerant circuit, for the cooling of air to be conditioned for the interior, which air conditioning system has a second evaporator for air cooling purposes which additionally contains a cold storage medium, the air to be conditioned optionally being able to be passed through each evaporator individually or through both evaporators jointly. According to an alternative embodiment, instead of the second evaporator, the evaporator is configured such that it has two subregions and in one of the two subregions contains a cold storage medium, the air to be conditioned optionally being able to be passed through each evaporator individually or through both evaporators jointly. The tubes in which the refrigerant flows through the evaporator can here be configured as multichannel tubes, one or more of the channels being filled with the cold storage medium.

Starting from this prior art, the object of the invention is to provide an improved heat exchanger. This object is achieved by a heat exchanger having the features of claim 1. Advantageous embodiments are the subject of the sub-claims.

According to the invention, a heat exchanger, in particular an evaporator for a motor vehicle air conditioning system for the cooling of air to be conditioned for the interior is provided, having a plurality of mutually adjacent, refrigerant-carrying tubes and having at least one cold store, in which a cold storage medium is provided. The evaporator here has two mutually parallel regions extending over the entire width, wherein the first region corresponds in its structure to a conventional evaporator, the cold store is disposed in an independent second region, which can be flowed through by at least a part of the refrigerant flow, and the first and the second region are connected to each other by at least one overflow opening. Via the overflow opening, at least a partial flow of refrigerant flows over from one region into the other region, i.e. refrigerant flows in both regions. Between the tubes of the first and/or of the second region of the heat exchanger there are disposed corrugated ribs, or other elements which enlarge the heat transfer surface. The fact that the first region substantially corresponds to that of a conventional heat exchanger means that existing tools can continue to be used, only the tools for the second region and for the creation of the overflow opening(s) must be newly procured. The second region—if the first region is designed in accordance with the previous construction—is relatively easily adaptable to the existing installation space and the cooling requirement. Furthermore, only one expansion member is necessary.

Because of the modular structure, an evaporator which is configured in this way can also be referred to as an “add-on” storage evaporator, i.e. to the, in principle, substantially conventional basic form of the evaporator is added a correspondingly configured cooling module.

Preferably, precisely two overflow openings are provided, though—in the case of a separate refrigerant feed—just one overflow opening may also be provided. Similarly, a plurality of overflow openings are possible, through which refrigerant can flow over from the first region to the second region and vice versa.

In at least one cold storage element there is preferably disposed at least one refrigerant-carrying tube. The cold storage elements can here be connected to one another, in particular by at least one reservoir.

In one arrangement of the refrigerant-carrying tube in the cold storage element, it can be plugged into the cold storage element filled with the cold storage medium or else can be configured directly therein, the cold storage medium preferably surrounding the refrigerant from all sides and, in particular, a tube-in-tube arrangement being provided.

Likewise, the cold storage element can be formed by a tube of U-shaped cross section, in particular having a plurality of chambers. In this case, the internal dimensions of the cold storage element preferably correspond to the external dimensions of the refrigerant-carrying tube in the corresponding region, so that the tubes bear full-facedly one against the other. A one-piece embodiment, for example formed by a correspondingly extruded tube having at least two channels, is also possible.

In the case of an arrangement fully within the cold storage element, the tube which carries the refrigerant and contains the cold storage medium is preferably configured as a double-walled flat tube, the refrigerant being located in the central region and the cold storage medium in the outer region. According to a further preferred embodiment, the double-walled flat part has webs, which connect the outer to the inner flat tube. The fact that the cold store has direct air contact produces very good dynamics in the heat transfer, so that, where necessary, i.e. in idle-stop operation, the full cold capacity is immediately available.

The tube containing the cold storage medium may also not fully surround the refrigerant-carrying tube. In this case, preferably, precisely three sides of the refrigerant-carrying tube are surrounded by the tube containing the cold storage medium. The tube containing the cold storage medium can here be configured with a U-shaped cross section and can surround the refrigerant-carrying tube, preferably a flat tube, partially, i.e. over a part of its periphery, the greatest part of the refrigerant-carrying tube preferably being disposed inside the tube containing the cold storage medium.

Preferably, the refrigerant-carrying tubes of the second region end in a reservoir, which is configured separate from and only by one or more overflow openings to a reservoir of the first region. This allows the heat exchanger, where appropriate, also to be retrofitted with a cold store, in particular the first regions—apart from the overflow openings—can however be identically configured, as in the case of conventional heat exchangers, so that the manufacturing costs, as a result of larger batch sizes and same tools for a large part of the component parts, are able to be lowered. Furthermore, the two regions can be put together separately and then connected to each other.

The tubes or channels carrying cold storage medium preferably end in a cold storage medium reservoir, through which the refrigerant-carrying tubes or channels project, which end in a separate reservoir. This allows the individual cold storage elements to be jointly filled with the cold storage medium, so that a simple and rapid filling of the tubes or channels carrying the cold storage medium is possible. Furthermore, the assembly can be simplified by the preferably one-piece design of the cold store in the case of a separate configuration of the refrigerant-carrying tubes and of the cold storage elements. A compensating space for, in particular, temperature-induced changes in volume of the refrigerant can thereby be provided. Furthermore, this allows a compact design of the second region.

Preferably, the first region has, in the direction of its width adjacent to the second region, a number of blocks which can be flowed through in different direction by the refrigerant, and the second region has at least one block, in particular a number of blocks which can be flowed through in different direction by the refrigerant. Here, the number and/or width of the individual blocks in the latitudinal direction of the evaporator preferably differs in the first region and in the second region. The first region preferably has directly adjacent to the second region two to four, in particular three blocks, and the second region has one to six blocks, in particular two to four blocks.

Preferably, flat tube rows of the first region and of the second region are mutually aligned, a flat tube of the second region also being able to be disposed, however, only behind every nth, in particular every second or third flat tube, of the first region, so that the air flow resistance is as low as possible, though the flat tube rows may also be disposed in irregular or offset arrangement (for example, centrally staggered), or the cold storage elements with the refrigerant-carrying tubes disposed therein may be arranged wryly relative to the other flat tubes of the evaporator. The number and shape of the flat tubes of the second region can be chosen in accordance with the desired heat quantity in the case of a vehicle stop.

The second region of the evaporator is preferably disposed, viewed in the normal air flow direction, after the first region of the evaporator, in particular directly following the evaporator, but an arrangement before the evaporator or somewhat remote from the evaporator is also possible in a second, in particular smaller evaporator part. Particularly in the case of a remote arrangement from the (main) evaporator, the size of the collector with cold store can be adapted in accordance with the existing installation space and/or the requirements. It is particularly advantageous that the existing evaporator does not have to be modified, or only very slightly, so that a relatively simple integration of the cold store into existing systems is possible. Existing tools do not have to be modified (or only very slightly). Only the tools for the cold storage region of the evaporator which is added on have to be procured.

The tubes which are flowed through by the refrigerant are preferably constituted by welded or folded flat tubes, or flat tubes which are deep-drawn or extruded from blanks and can be configured both rounded and square. Oval tubes or round tubes can also however be used. As materials, in particular aluminum and aluminum alloys can enter into consideration, but the use of other suitable, good heat-conducting materials of choice is also possible.

The cold store preferably consists of aluminum, in particular internally and/or externally coated aluminum (by aluminum also being understood an aluminum alloy), where appropriate also copper, a copper-zinc alloy, synthetic resin or plastic. An aluminum reservoir has the advantage that it can be soldered together with the other parts of the evaporator without difficulty. Preferably it is in the form of an extruded flat tube having a plurality of channels, one part of the channels containing the cold storage medium and the other part of the channels containing the refrigerant. The design may also, however, be multipart.

The latent or storage medium is preferably constituted by a PCM material (phase change material), which preferably contains or is formed from congruently melting media, in particular decanol, tetra-,penta- or hexadecane, Li—ClO₃3H₂O, aqueous salt solutions or organic hydrates. In the storage medium nucleating agents can also be provided, which accelerate the crystallization.

The phase change temperature of the storage medium lies preferably within a range from 0° C. to 30° C., preferably from 1° C. to 20° C., in particular from 2° C. to 15° C., in particular preferably from 4° C. to 12° C.

Inside the cold storage element—irrespective of whether it wholly or only partially surrounds the refrigerant-carrying tube—inlays such as ribbed sheet-metal plates, preferably of aluminum, though other metals or plastics are also suitable, or other turbulence inlays such as nonwovens or knitted fabrics, for example of plastic or metal, or foams, for example metal foams or plastic foams, can be provided. The inlays serve to improve the heat transport and to increase the inner surface in order to accelerate the crystallization of the storage medium.

The two regions are preferably flowed through in series, so that only one expansion member is provided for both regions. The refrigerant inlet is here preferably provided on the collector of the first region.

Preferably, the heat exchanger has the following dimensions (with respect to the measurements, reference is made to FIGS. 8 and 9).

The total depth T of the heat exchanger is preferably 23 to 200 mm, in particular 35 to 80 mm, particularly preferably 60+/−10 mm.

The installation depth T′ is preferably 20 to 150 mm, in particular 25 to 90 mm. The installation depths T1 and T2 of the flat tubes of the evaporator in the region without cold store are generally mutually corresponding (symmetrical shaping of this evaporator region).

The widths b1 and b2 of the flat tubes of the evaporator in the region without cold store are preferably mutually corresponding, a flat tube of one row preferably being respectively aligned with a flat tube of the other row. The widths b1 and b2 are preferably 0.8 to 4 mm, in particular 1.3 to 3.5 mm.

The transverse spacing q1 of the first flat tube row is preferably 4 to 20 mm, particularly preferably 5 to 13 mm. It preferably corresponds to the transverse spacing of the second flat tube row of the evaporator.

The height of the corrugated rib of the first flat tube row is thus preferably 3 to 18 mm, in particular 4 to 10 mm. It preferably corresponds to the corrugated rib height of the second flat tube row of the evaporator.

The evaporator, in the region of the cold store, has flat tubes, which contain the cold storage medium in the outer cold storage medium channels, having widths b3 from preferably 2.0 to 10.0 mm, in particular from 3.0 to 8.0 mm. The width b4 of the flat tubes disposed therein, in whose refrigerant channels the refrigerant flows, is preferably 0.6 to 2.5 mm, in particular 0.9 to 1.5 mm.

The installation depth T3 of the flat tubes of the evaporator in the region with cold store is preferably 5 to 70 mm, particularly preferably 10 to 30 mm.

The transverse spacing q3 of the flat tubes of the evaporator in the region with cold store is preferably a multiple of q1, in order to keep the pressure decrease of the through-flowing air low, but may also correspond to q1. Particularly preferred values are two and three.

The height H1 of the cold storage medium reservoir is preferably 3 to 25 mm, in particular 3 to 15 mm, but is preferably as small as possible in order to save installation space and keep the cross section through which air can flow as large as possible.

The invention is explained in detail below with reference to an illustrative embodiment with variants, partially with reference to the drawing, wherein:

FIG. 1 shows a perspective view of a heat exchanger with collector according to the first illustrative embodiment,

FIG. 2 shows a side view of the heat exchanger of FIG. 1,

FIG. 3 shows a selective perspective view of the heat exchanger of FIG. 1, with removed collecting box and collecting tube,

FIG. 4 shows a further perspective view of a region of the heat exchanger of FIG. 1, with laterally opened reservoir and collecting tube,

FIG. 5 shows a sectioned side view of the heat exchanger of FIG. 1,

FIG. 6 shows a detailed view of an overflow opening,

FIG. 7 shows a sectioned detailed view of the heat exchanger of FIG. 1 in the region of the cold store,

FIG. 8 shows a section transversely through the heat exchanger of FIG. 1,

FIG. 9 shows a section through the lower region of the heat exchanger of FIG. 1,

FIG. 10 shows a perspective view of the heat exchanger of FIG. 1, with schematic representation of the refrigerant flow path,

FIG. 11 shows a schematic sectional representation of the heat exchanger of FIG. 1, in illustration of the refrigerant flow path,

FIG. 12 shows a schematic side view of the heat exchanger with cold store of FIG. 1, in illustration of the refrigerant flow path,

FIGS. 13 a, b show schematic representations of the refrigerant flow path according to a first variant,

FIGS. 14 a, b show schematic representations of the refrigerant flow path according to a second variant,

FIGS. 15 a, b show schematic representations of the refrigerant flow path according to a third variant,

FIGS. 16 a, b show schematic representations of the refrigerant flow path according to a fourth variant,

FIGS. 17 a, b show schematic representations of the refrigerant flow path according to a fifth variant, and

FIGS. 18 a, b show schematic representations of the refrigerant flow path according to a sixth variant.

A motor vehicle air conditioning system for controlling the temperature of the motor vehicle interior having a refrigerant circuit (in the present case R134a, though CO₂ or another refrigerant, for example, may also be used) of which only the evaporator 1, with injection tube 2 and suction tube 3, is represented, has a cold store 4 in order to provide a sufficient cooling capacity at least for a short while even when the engine is stopped, which cold store consists of a plurality of cold storage elements 5, in the present case twenty-two, which are filled with a cold storage medium. The cold storage elements 5 are formed by regions of specially shaped, aluminum flat tubes 6, discussed in greater detail at a later point. Serving in the present case as the cold storage medium is decanol. Alternatively, tetra-,penta- or hexadecane, for example, are also suitable.

The normal air flow direction is indicated in FIGS. 1 and 2 by arrows. The evaporator 1 has in the larger part located on the leading edge a region 1′ with structure corresponding to that of a conventional evaporator, having two rows of flat tubes 7 and corrugated ribs 8 disposed therebetween. The flat tubes 7 end respectively in a reservoir 9. As can be seen from FIGS. 1 and 2, the refrigerant enters on the narrow side of the upper reservoir 9 on the trailing edge into the evaporator 1 and leaves it on the same narrow side in the leading edge region of the reservoir 9.

The other region of the evaporator 1, namely the cold storage region 1″, which, as a matter of principle, is configured separate as an independent region of the evaporator 1 and in which the cold storage elements 5 are provided, is formed by the smaller, trailing edge part of the evaporator 1.

As can be seen, in particular, from FIG. 8, the cold store flat tubes 6 in the cold storage region 1″ and the conventional flat tubes 7 in the region 1′ are arranged such that, in the case of the first, third, fifth, etc. flat tube 7, a cold store flat tube 6 is respectively arranged flushly in alignment with the same in the air flow direction.

Since the interspaces between the cold store flat tubes 6, which in the present case are configured in the air flow direction narrower, but transversely thereto wider than the flat tubes 7, are because of this arrangement relatively wide, the flow resistance for the air flowing through the evaporator 1 is virtually negligible in comparison to the flow resistance of the first region 1′ of the evaporator 1 and can be substantially disregarded for the design of the evaporator 1 with regard to the air through-flow, so that, relative to a basic variant of the evaporator without the cold storage region 1″, no or only minor recalculations have to be made with regard to the air flow. Alternatively, the flat tubes 6 and 7 can be arranged in any other chosen way, for example in alignment or staggered.

The cold store flat tubes 6 have a double-walled structure having a plurality of refrigerant channels 6′ and cold storage medium channels 6″, the refrigerant channels 6′ being arranged on the inside (see FIG. 8). The cold store flat tubes 6 are here arranged such that the cold storage medium channels 6″ serving as cold storage elements 5 respectively end in one of two cold storage medium reservoirs 10, so that the cold storage element 5 has only a single cavity, which—apart from a compensating space—is fully filled with the cold storage medium. The filling is realized in a single operation via an opening in the cold storage medium reservoir 10. After the filling, the opening is securely closed, so that unauthorized opening is reliably prevented.

According to a variant not represented in the drawing, inside the continuous cavity elements are provided, such as, in the present case, a synthetic non-woven, which serve to improve the heat transport and to increase the inner surface so as to accelerate the crystallization of the latent medium.

The refrigerant channels 6′ project with their ends respectively through the corresponding cold storage medium reservoirs 10 and end respectively in a reservoir 12 configured separate from the reservoir 9, in the present case in the form of a tube, which reservoirs are hereinafter referred to as collecting tubes.

Each of the collecting tubes is connected by a respective slot-like overflow opening (not represented) to a slot-like overflow opening 13 of the reservoirs 9 disposed at a corresponding location (see FIG. 5).

The evaporator 1 is flowed through in its conventional region 1′ in such a way that the refrigerant flow is deflected twice in the evaporator width, before being deflected depthwise counter to the air flow direction. In the leading edge region it is likewise deflected twice widthwise. The evaporator in question thus has six blocks B1 to B6, respectively three blocks being provided in the latitudinal direction of the evaporator 1 (i.e. in the row which is first flowed through, the blocks B1 to B3, and in the row which is last flowed through, the blocks B4 to B6) and the individual blocks B1 to B6 of the two block rows are flowed through in the cross-counterflow operation. This refrigerant flow path is represented in FIG. 10 by arrows shown with solid line.

Via the overflow opening 13 in the reservoir 9, shortly after the entry of the injection tube 2 into the reservoir 9 in the first block B1, a part of the refrigerant is branched off from the refrigerant flow, which refrigerant part makes its way via the overflow opening into the collecting tube and is distributed via the collecting tube over the refrigerant channels 6′ of the flat tubes 6, which in the present case are flowed through in one direction, i.e. over the entire width of the evaporator 1 in the cold storage region 1″ only one storage element block is present. The branched-off part of the refrigerant is fed via the second overflow opening provided on the second collecting tube, and the corresponding second overflow opening 13 on the other reservoir 9, back to the main refrigerant flow, which in this region of the block B3 is deflected depthwise to the block B4. The refrigerant flow path of the partial flow is represented in FIG. 10 by arrows shown with dashed line.

Instead of the previously described structure, the reservoirs can be constructed differently, in particular in panel construction.

In the other figures, different variants of the refrigerant conductance through the cold storage region 1″ of the evaporator 1 is represented, which are designed to ensure that the cold storage medium in all cold storage medium channels 6″ passes as evenly as possible through its phase change. For this it is necessary to ensure that the branched-off partial flow of the refrigerant is distributed as evenly as possible over the flat tubes 6 with their refrigerant channels 6′.

FIGS. 13 a and 13 b show a circuitry variant having 3-block circuitry in the storage element. The refrigerant from each of the first three blocks B1 to B3 of the conventional region 1′ of the evaporator 1 is here distributed into the associated storage element block (i.e. there are three storage element blocks) and recirculated. As a result of the reduced number of parallel-connected flat tubes per storage element block, a better refrigerant distribution than the previously described illustrative embodiment is obtained.

According to one modification of this variant (not represented in the drawing), more than just one outlet and inlet opening per block of the conventional region of the evaporator are provided, so that, for example, six storage element blocks are provided.

According to the second variant represented in FIGS. 14 a and 14 b, the refrigerant flow is guided in the storage element in accordance with that in the serial evaporator (i.e. twofold deflection widthwise). In this circuitry, in the event of a one-off overflow from the conventional region 1′ of the evaporator 1, only one-third of the flat tubes of the storage element is parallelly subjected to refrigerant. Other circuitries are likewise possible in the cold storage region 1″, for example five storage element blocks may be provided.

FIGS. 15 a and 15 b show a direct refrigerant inlet into the refrigerant storage region 1″ instead of into the conventional region 1′ of the evaporator 1. With this variant, a preferred supply to the storage element block can be ensured should too little refrigerant be able to be drawn off from the conventional region 1′ of the evaporator 1 through the passage openings.

In FIGS. 16 a and 16 b, a split refrigerant inlet for the conventional region 1′ of the evaporator 1 and the cold storage region 1″ is provided as a fourth variant, i.e. the branching-off of the partial flow for the cold storage region 1″ is realized still prior to the entry of the refrigerant into the evaporator 1 in the region of the injection tube. In this case, the refrigerant distribution over the two inlet openings can be optimized, where appropriate, via the injection tube diameter and the pressure loss in the conventional region 1′ of the evaporator 1 and in the cold storage region 1″.

FIGS. 17 a and 17 b show a circuitry variant having a serial connection of the cold storage region 1″ and, downstream, of the conventional region 1′ of the evaporator 1. In this variant, the cold storage medium in the cold storage region 1″ is first frozen by means of the refrigerant flow (in the present case, the entry is made from below), before the refrigerant then in the normal flow guidance passes through the conventional region 1′ of the evaporator 1. Since the whole of the refrigerant flow is conducted fully through the cold storage region 1″, this variant freezes the cold storage medium fastest.

In FIGS. 18 a and 18 b, a further circuitry variant is represented, according to which, once again, a partial flow is branched off in the first block B1. In the present case, the cold storage region 1″ here has two blocks, which are flowed through in different directions. The refrigerant from the cold storage region 1″ here enters into the reservoir of the third block B3 and flows jointly through the same, i.e. the third block B3 is flowed through by the whole of the refrigerant, while the first two blocks B1 and B2 are only flowed through by a (larger) refrigerant partial flow. According to the represented variant, the two blocks of the cold storage region 1″ have a different width, the block which is first flowed through being narrower than the block which is subsequently flowed through.

The circuitry variants allow improved dynamics of the loading and unloading operation to be optimized and the outlet temperature profile of the evaporator when the vehicle is stopped to be homogenized.

All variants are independent of the refrigerant (R134a, R744), of the collector design (curved collector, panel construction) and block circuitry of the serial evaporator (for example, 2 or 4-block circuitry). 

1. A heat exchanger, in particular an evaporator, in particular for a motor vehicle air conditioning system having a plurality of mutually adjacent, refrigerant-carrying tubes and having at least one cold store, in which a cold storage medium is provided, wherein the evaporator has two mutually parallel regions extending over the entire width, wherein the first region corresponds in its structure to a conventional evaporator, the cold store is disposed in an independent second region, which can be flowed through by at least a part of the refrigerant flow, and the first and the second region are connected to each other by at least one overflow opening.
 2. The heat exchanger as claimed in claim 1, wherein two overflow openings are provided.
 3. The heat exchanger as claimed in claim 1, wherein in at least one cold storage element there is disposed at least one refrigerant-carrying tube.
 4. The heat exchanger as claimed in claim 1, wherein the tube which carries the refrigerant and/or contains the cold storage medium is a double-walled flat tube, the refrigerant being located in the central region and the cold storage medium in the outer region.
 5. The heat exchanger as claimed in claim 1, wherein the refrigerant-carrying tubes of the second region end in a reservoir, which is configured separate from and only by one or more overflow openings to a reservoir of the first region.
 6. The heat exchanger as claimed in claim 1, wherein the tubes or channels carrying cold storage medium end in a cold storage medium reservoir, through which the refrigerant-carrying tubes or channels project, which end in a separate reservoir.
 7. The heat exchanger as claimed in claim 1, wherein the first region has, in the direction of its width adjacent to the second region, a number of blocks which can be flowed through in different direction by the refrigerant, and the second region has at least one block, in particular a number of blocks which can be flowed through in different direction by the refrigerant, and the number and/or width of the individual blocks in the latitudinal direction of the evaporator differs in the first region and in the second region.
 8. The heat exchanger as claimed in claim 7, wherein the first region has directly adjacent to the second region two to four, in particular three blocks, and the second region has one to six blocks, in particular two to four blocks.
 9. The heat exchanger as claimed in claim 1, wherein the phase change temperature of the cold storage medium lies within a range from 0° C. to 30° C., preferably 1° C. to 20° C., in particular from 2° C. to 15° C., in particular preferably from 4° C. to 12° C.
 10. The heat exchanger as claimed in claim 1, wherein in the cold store there is disposed at least one inlay.
 11. An air conditioning system with cold store, in particular for a motor vehicle, having a refrigerant circuit, characterized by an evaporator according to claim
 1. 